The present invention relates to point-of-use water treatment system (WTS) units for above or below countertop use in homes or offices for the purposes of removing contaminants from water.
The present invention minimizes or overcomes several problems associated with previous point-of-use home or office water treatment system (WTS) units. These WTS units are often connected to a faucet using a faucet diverter valve assembly. Water can be supplied directly from the faucet, or using the faucet diverter valve assembly, can be routed through a WTS unit for removal of contaminants prior to being dispensed from a faucet. The WTS units often include a carbon block filter to remove particulates, an ultraviolet (UV) bulb for destroying microorganisms found in water, and a flow meter to monitor the quantity of water treated over a specified period of time.
A first problem many WTS units encounter is that filter closures can be difficult to remove from or install on WTS unit filter housings. This is particularly true of closures that rely upon threaded connections. The closures combine with the filter housings to form closed pressure vessels in which filters are stored. The diameters of filters are ideally as large as possible to increase the capacity and life expectancy of the filters. Similarly, the diameter of filter housings must be large to accommodate the filters. Conventional threaded connections between the filter closures and filter housings, which are both usually made of plastic, often xe2x80x9cweldxe2x80x9d together. This phenomenon is known as galling. The xe2x80x9cweldingxe2x80x9d action is partially attributable to the long period of time between filter changes and also to the wet and warm environment in which WTS units operate.
WTS units often include a UV (ultraviolet) bulb for destroying microorganisms in the water to be treated. These UV bulbs typically operate continuously. After water has not been run through a WTS unit for a significant period of time, such as overnight, heat from the UV bulb and other electrical circuitry can cause heat to build up inside and elevate the temperature of water stored within the WTS unit. The resulting increased temperature contributes to plastic creep and the xe2x80x9cweldingxe2x80x9d together of the threads on the filter closure and filter housing. Because of the large area of contact between the threads, considerable force may be required to break the xe2x80x9cweldxe2x80x9d on the threads and release the closure from the filter housing.
Alternatively, some WTS units use bayonet mounted filter closures. A problem with this type of mount is that a filter closure must be accurately aligned with a housing to effect mounting of the filter closure to the filter housing. Also, even with a bayonet mount, there is still significant joint contact area between the filter closure and the filter housing. Again, significant force may be required to break the filter closure free from the filter housing after a long period of attachment.
A second problem associated with WTS units having UV bulbs is the build up of heat within the WTS units. Adverse consequences related to elevated temperature include structural degradation of plastic components over time due to creep, discoloration of plastic components, and decreased reliability of electrical circuitry. Also, the temperature of water stored overnight within a WTS unit can become uncomfortably warm to the touch when discharged from the WTS unit. Therefore, it is beneficial for a WTS unit to be designed to minimize its internal heat buildup.
Further, most WTS units use plastic molded decorative outer housings to enclose internal components. These plastic outer housings decrease in strength as temperature increases. If the WTS unit is to be wall mounted and must rely solely upon the strength of the outer housing, then the outer housing must be relatively thick, made of high strength plastic and resistant to creep induced by high temperatures and mechanical loads. Accordingly, expensive specialty plastics may be required in making such outer housings.
A third problem associated with WTS units having UV bulbs is that UV bulbs are cumbersome to change. The UV bulbs have a limited lifetime and must be periodically changed. While the UV light emitted by the bulbs is beneficial in destroying chemical bonds in microorganisms, hence severely inhibiting their ability to replicate or reproduce, the UV light can also be harmful to human eyes. Consequently, the UV bulbs must be mounted without UV light exposure to the installer. Often this requires numerous steps such as connecting a UV bulb to a power source, closing a housing about the UV bulb to prevent UV light exposure, and then energizing the UV bulb to insure that the UV bulb will properly operate. Ideally, a UV bulb could be easily and quickly installed with the UV bulb immediately lighting upon installation to show that it is operating properly while preventing direct exposure of the UV light to the operator.
A fourth problem common to WTS units having UV light disinfection is that water flowing through a UV tank assembly may not be uniformly treated or exposed to UV light. A UV bulb is typically mounted in a UV tank assembly with water passing around the UV bulb. All portions of the water should receive a predetermined minimal exposure or dosage of UV light. Depending on how the water is directed through the UV tank assembly, portions of the water flow receive lesser or greater amounts of exposure. That is, portions of water that pass most quickly through the UV tank assembly tend to receive less UV light exposure than portions of water that take a slower path and have a longer residence time. Ideally, all the water would receive the same predetermined minimum dosage of UV light to ensure a desired kill or destruction rate without unnecessarily overexposing certain portions of the water flow. Without steady or plug flow through the UV tank assembly, this objective cannot be optimally met. Plug flow refers to a xe2x80x9cplugxe2x80x9d or mass of water moving together through the system. Plug flow avoids uneven flow rate of water through the system.
Some WTS units utilize water transporting Teflon coils surrounding a UV bulb to achieve a generally uniform flow rate for all water. However, the Teflon coils can deteriorate and/or cloud over. Also, the Teflon coils can be damaged by heat. Further, water borne contaminants may reduce the transmissibility of light through the Teflon coils over time. Therefore, the coils must be cleaned or replaced in certain water conditions.
One example of a UV tank assembly that addresses this problem is shown in U.S. Pat. No. 5,536,395. A tank includes a generally cylindrical main portion and a reduced diameter neck portion. The cylindrical portion has attached thereto an inlet and a coaxially aligned annular baffle plate with circular openings therein. Water enters the inlet inducing circumferential water flow and then passes through the openings in the baffle plate. As a result, water flowing downstream from the annular baffle plate travels in a generally spiral motion about a UV bulb disposed within the UV tank assembly. The water then passes to the reduced neck portion before exiting the tank through an outlet fitting. While this UV tank assembly design provides satisfactory flow characteristics, the tank is expensive and difficult to manufacture due to numerous deep drawing operations required to form the tank. Further, there are numerous machining operations which must be performed on stainless steel components which also increases the complexity and cost of manufacture.
Another drawback conventional WTS units have is the use of a plurality of tubes to fluidly interconnect the various components of the WTS units. Individual tubes are typically used to interconnect inlets, outlets, UV subassemblies and filter subassemblies and flow monitoring devices. The large number of tubes used makes assembly inconvenient and time consuming. Further, tubes can become brittle over time and may eventually have to be replaced. With this complexity of tubes and tube clamps, replacement of parts is difficult for the average consumer. Also, as the tubes are non-structural members, additional supporting members must be used to support components such as flow meters and UV and filter subassemblies apart from support provided by decorative housings of the WTS units. Moreover, designs utilizing tubes makes optimization of the compactness of a WTS unit difficult.
The present invention includes designs and features which overcome, or at least minimize, many of the problems identified above which are encountered by previous water treatment system units.
The present invention includes a WTS unit which has a unique filter closure and attachment mechanism that allows the closure to be easily and quickly secured to and removed from a filter housing. The filter housing has a filter chamber for receiving a filter. The closure releasably seals with the housing assembly to form a closed pressure vessel. The attachment mechanism is ideally attached to the closure and utilizes a mechanical advantage, preferably in the form of a pivoting handle which cams a pair of reciprocating lock blades into and out of engagement with one or more blade receiving openings on the filter housing.
The present invention also covers a WTS unit having a UV tank assembly, a UV bulb assembly received within the UV tank, and a heat dissipating support plate juxtaposed the UV tank assembly. This arrangement allows heat generated by the UV bulb assembly and transferred to the UV tank to be readily transferable to the support plate and then the atmosphere. Use of the heat dissipating support plate also allows low strength decorative outer housing components to be used with the WTS unit as the support plate provide structural support to internal components and for wall mounting of the WTS unit.
A point-of-use water treatment system is disclosed having a base, a UV tank assembly, an electrical connector cap assembly and a UV lamp assembly. The cap assembly attaches to the UV tank assembly. The UV lamp assembly simultaneously mounts to the cap assembly and UV tank assembly to form a closed pressure vessel and to electrically communicate with the cap assembly. Ideally, a fluid seal is created between the UV lamp assembly and the tank assembly while the UV lamp assembly bayonet mounts to the cap assembly to create electrical communication therebetween. Further, the UV bulb assembly preferably includes a light pipe which is visible from the exterior of the WTS unit to indicate when the UV lamp assembly is operating.
A UV tank assembly is provided which includes a generally cylindrical sleeve and first and second longitudinally spaced apart annular baffle plates. The first baffle plate is ideally planar and has a plurality of openings therein. The second baffle plate is preferably vaned. When a UV lamp assembly is placed within the UV tank assembly, water flowing from the first baffle plate to the second baffle plate travels in a spiral path about a UV bulb providing the water generally uniform exposure to UV light. This particular UV tank assembly is relatively simple in construction and inexpensive to manufacture.
The invention further includes a WTS unit having a UV subsystem, a filter subsystem, a flow monitor, a base and a bi-planar manifold. The manifold has first and second halves which are joined together to cooperatively provide conduits which fluidly interconnect the filter subsystem, the UV subsystem and the flow monitor. The filter subsystem rests upon a first plane of the manifold and the UV subsystem rests upon a second elevated plane of the manifold with the flow monitor being positioned in an envelope created beneath the second plane of the manifold and the base of the WTS unit. This arrangement allows for a compact design for the WTS unit.
It is an object of the present invention to provide a WTS unit which has a filter closure which is easily installed on and removed from a filter housing even after the filter closure has been mounted to the filter housing for an extended period of time.
Another object is to provide a filter closure having an attachment mechanism which utilizes a mechanical advantage such that undue force or strength is not required by a user to effect removal of the filter closure.
An additional object is to provide a high thermal conductivity and high strength support plate to support major components of a WTS unit while enhancing heat dissipation from the WTS unit.
Yet another object is to provide a WTS unit having a UV lamp assembly which allows a UV bulb, in a single quick movement, to be concurrently electrically connected to a power supply while fluidly sealing with a UV tank assembly thereby eliminating exposure of UV light to a WTS unit user. This eliminates the extra step of locating and attaching a wiring harness to complete assembly.
Another object is to provide a UV tank assembly which is inexpensive to manufacture yet cooperates with a UV bulb to allow generally uniform flow and UV light exposure to water passing by the UV bulb.
Still a further object is to provide a WTS unit having a bi-planar manifold assembly which interconnects with the major components of the WTS unit to provide simple yet reliable fluid connections therebetween. The manifold assembly provides structural support to other subcomponents and partially defines an envelope for placing a flow meter and monitor assembly.
Another object is to provide a WTS unit having a UV bulb assembly with a light pipe thereon, the light pipe being replaceable with the UV bulb assembly and extending through an opening in the outer housing of the WTS unit to indicate when a UV bulb is operating.